Question: photo navigation shut down

I have a Oregon 450. I have geotagged (geosetter) several photos of huts in the alps for photo navigation.
Everything works fine till I exeed the number of 18 photos. With the 19th photo the Oregon shuts down when I start browsing for a hut.
Average photo size is around 80KB. The photos are on SD but the same happens when they are on the Oregon.

Any ideas???

I want of course upload much more than 18 mountain huts!!